Heating and cooling systems are known that comprise a fluid circuit through which a fluid circulates under pressure. An example of this type of system is a closed circuit central heating system, in which water flows in a loop from a boiler, through a series of hot-water radiators and then back to the boiler.
A problem with this type of closed circuit system is that the circulating fluid can become contaminated, resulting in a reduction in the performance efficiency of the heating or cooling system and possibly also leading to total system failure. The most common sources of contaminants in the circulating fluid are: corrosion, lime scale and microbiological growths (bacteria or fungi). Debris and sludge in the circulating fluid of a heating or cooling system can lead to blockages, leakage, and premature system failure. Approaches to addressing the problem of circulating fluid contamination include flushing of the system to remove any debris in the fluid circuit, and introducing a treatment additive, such as an inhibitor, into circulating fluid for the purpose of preventing or resolving contamination build-up.
A known device for introducing additives into the circulating fluid of a sealed commercial heating or chilled water system is a dosing pot. The dosing pot comprises a closed vessel that is connectable into the fluid circuit of the system and allows an additive to be received therein. With the dosing pot isolated from the fluid circuit, an additive is introduced into the vessel. The dosing pot is then opened into the fluid circuit to allow the additive to pass into the circulating fluid flowing through the vessel. The dosing pot is then isolated from the fluid circuit again, until such time as further dosing of the system is to be performed. This apparatus may therefore be perceived as ‘normally closed’ to the system fluid flow.